1. Technical Field
Various embodiments generally relate to semiconductor technology, and more particularly, to a nonvolatile memory device and a method for manufacturing the same.
2. Related Art
As efforts for improving a degree of integration of a nonvolatile memory device with a 2-dimensional structure in which memory cells are formed as a single layer on a substrate, reach a limit, a nonvolatile memory device with a 3-dimensional structure, in which memory cells are three-dimensionally arranged on a substrate to improve a degree of integration, has been suggested. Since the nonvolatile memory device with a 3-dimensional structure may efficiently use the area of the substrate, the degree of integration may be improved when compared with the memory cells which are arranged two-dimensionally. Also, since this technology is not based on a method of repeating a step of forming memory cells on a plane but memory cells are formed through blanket processing on a plurality of word lines which are vertically stacked, a manufacturing cost for a unit cell may be significantly decreased.
A nonvolatile memory device with a 3-dimensional structure generally includes a structure with a line type channel layer and a structure with a U-shaped channel layer. In the case of the structure with a U-shaped channel layer, pipe coupling transistors are used to couple memory cell strings.
In the nonvolatile memory device with a 3-dimensional structure, in order to divide stacked word lines into a plurality of memory blocks, slits are formed to pass through word lines. In an etching process for forming the slits, problems may be caused in that structures formed under gate electrodes of the pipe, coupling transistors hereinafter, referred to as “pipe gate electrodes”, are likely to be damaged.